1. Field of the Invention
The present invention relates generally to submersible mixer support systems and more particularly to a support system for low speed submersible mixers for use in sewage system treatment facilities and the like.
2. Description of the Prior Art
The use of large propellered slow rotation devices to produce a large flow is known for preventing ice formation, providing fresh water for fish farms, blending low viscosity liquids in process mixing operations, and providing circulation in sewage treatment facilities. Generally, for servicing and inspection purposes, the mixing devices have to have the capability of being removed by service personnel at the surface of the body of liquid being mixed as the liquid is oftentimes inhospitable to divers and the like.
Traditionally, these mixers have been slidably mounted to a mast support system to furnish the desired removability capability. A four inch (4") square mast is secured to the bottom of the body of liquid and the mixer is fastened to the mast with a sliding bracket allowing the mixer to slide up and down the mast to be positioned at the desired operating location and facilitate removal. Because these mixers operate in harsh environments and the slow rotation of the large propeller blades produce tremendous forces and twisting loads on the mixers and the masts, many problems have arisen with the single mast systems. In particular, the single mast systems have exhibited mast failure, i.e., the brackets which hold the mixers subject the masts to fretting wear thereby initiating unintended and undesirable oscillatory movements of the mixing devices. Such problems create the need for frequent repairs and replacements of the masts and propellered mixer units requiring downtime for the entire mixing systems which, particularly in the case of sewage treatment systems, is undesirable as the systems cannot continue to operate without the mixing devices in place and functioning.